In recent years, as the performance of a semiconductor device becomes higher, a semiconductor device is in increasing demand particularly in in-vehicle equipment or in a rotating electrical machine for a vehicle. In in-vehicle equipment, the respective components are in the process of downsizing. In a rotating electrical machine for a vehicle, as wiring is simplified and mountability is improved by integrating a rotating electrical machine main body and a controller, downsizing and weight reduction of semiconductor devices used therein are required accordingly. In particular, a use environment of in-vehicle equipment or the like is harsh, and thus, additionally, high reliability and a long life are further required.
Conventionally, some MOS-FETs mounted on a semiconductor device are connected in series in a pair so as to form an upper arm and a lower arm, respectively. A semiconductor device has been proposed having a structure in which, a source electrode or a gate electrode of each MOS-FET and an external terminal are joined using an internal lead via solder, a coupling lead portion is provided in the internal lead joined to the source electrode of the MOS-FET which forms the upper arm so that the upper arm and the lower arm are electrically connected to each other, and the coupling lead portion is solder joined to part of a base plate on which the MOS-FET forming the lower arm is mounted and with which a drain electrode is brought into abutment.